We first started reporting on breakthroughs in medical 3D printing in July 2011, so we wanted to revisit this technology to see how things are progressing. Since July 2011, 3D printing has made some tremendous strides in the medical field: models of stints, artificial limbs and replacement skulls can now all be replicated using this emerging technology. The number of 3D printers being sold into the medical field is expected to double over the next four years and this is happening all around the world. Canadian researchers in Uganda are now able to help in the area of prosthesis with the help of 3D printing. What normally would have taken six days to produce can be done in six hours.
It’s difficult for many Ugandans to afford prostheses since 38 per cent of the population live on less than $1.25 US a day. They would need to pay at least $300, excluding hospital fees and travel expenses, for a prosthesis, says Mitchell Wilkie, CBM’s director of international programs. And since children grow an average of two centimetres a year, they would need a new prosthesis every six months, making it unaffordable for the average Ugandan.
During a five-day visit to Kampala in January, the researchers used a 3D printer to make sockets, the customized part of a prosthesis that attaches to an individual’s body and forms to the thigh for those with amputations below the knee. They then connected the sockets to the standard pylons and feet that the Red Cross provides for prosthetics in developing countries to complete the replacement limbs. Matt Ratto, a Toronto professor and principal investigator for the project, says he believes this combination is the world’s first 3D-printed leg to be used outside laboratories and test environments
The main issue for Ugandans, however, isn’t the cost of prosthetics or hospital services, Ratto says. It’s access to skilled people who can fit them. There are approximately twelve prosthetic technicians in Uganda, according to CBM. And there are about ten facilities where prosthetics can be made in the country, adds Malcolm Simpson, chief executive officer of the project’s partner hospital. This is where 3D printers could help. “The 3D technology we’ve introduced in Uganda cuts this work down to as little as six hours,” says Ratto. It takes just a few minutes to do a 3D scan of a residual limb and use software to shape the prosthesis. Then the printer takes a few hours to produce the customized socket from the scan. The Ugandan project will continue over the next six months as the Toronto researchers study the comfort and durability of the 3D-printed sockets, he says.
Tracheal reconstruction is another arena were 3D printing can play a vital role. The trachea, also called the windpipe, is a tube that connects the pharynx and larynx to the lungs. It allows the passage of air, and so is present in all air-breathing animals with lungs. One of the biggest challenges surgeons face in tracheal reconstruction is that the length of the trachea is fixed. When a doctor removes a long and diseased section of a trachea, they need enough trachea length to put the two healthy ends back together.
With help from his mentor, Daniel Grande, PhD, director of the Orthopedic Research Laboratory at the Feinstein Institute, twenty-eight-year old Todd Goldstein, investigator at the Feinstein Institute for Medical Research modified a Makerbot Replicator 2x Experimental 3D printer to print with living cells. First, MRI and CAT scans are used to replicate a 3D computer design of a patient’s trachea. Once the design is programmed into the printer, two types of materials begin to build the trachea: a syringe comprised of living cells called ‘bio-ink’ and polylactic acid, or PLA, which is a naturally occurring filament.
Layer by layer, the printer will start building the scaffold, or the frame of the trachea ring, with PLA. Next, the machine switches and fills in the void space it created with the cells, Goldstein said. The printing process can take up to two hours depending on the segment size. Goldstein said his team’s proof-of-concept model suggests that the cells are able to survive the printing process and that successful research conducted in animal models offers further promise. Goldstein and his colleagues still have a long way to go before they can use their prototypes in humans, but rapid progress is being made day by day and there is hope that within two years they will be ready to apply to the FDA for approval.